How To Make Spanish Red Pepper Sauce: Romesco

Romesco is the ultimate summer vegetable sauce. Made from stale bread (!) and burned vegetables (!) and transformed by the power of olive oil and a blender, to know this sauce is to love it. This Spanish sauce is silky like the best pesto — full of body and richness from ground nuts and a punch of flavor from garlic. But romesco has something pesto doesn’t: a generous kick of heat from cayenne pepper and a vibrant orange hue.

Consider romesco your new-go-to kitchen condiment that pairs well with just about everything from grilled seafood and charred vegetables, to tortilla chips and toasted bread. Here is everything you need to know about making romesco sauce at home.

(Image credit: Joe Lingeman)
What Is Romesco Sauce?
At its simplest, romesco is a nutty red pepper sauce that hails from the Catalonia region of Spain. Traditionally served with charred sweet onions or spooned over fish, this versatile sauce can improve everything from grilled vegetables to grain bowls with a single swish. Variations are made with or without tomatoes and many are thickened with both nuts and bread or breadcrumbs.

Here’s the thing you need to know about romesco: Although it’s a simple blender sauce, you’ll get a ton more flavor from doing a bit of prep work before puréeing.

(Image credit: Joe Lingeman)
Building a Delicious Sauce
Use 2 types of nuts: Toast a combination of skinned almonds and hazelnuts. Skinned almonds are easy to find in the grocery store, but peeling the hazelnuts is labor-intensive. You can use this trick (a boiling water and baking soda bath) for peeling them at home. Also, here’s how to toast nuts in the oven if you need a quick refresher.
Stale, toasted bread required: Use a broiler to toast a slice of bread — something with a hearty crumb like country or sourdough (no sandwich slices or whole wheat loaf here). And this slice of bread doesn’t need to be soft or fresh — make the most of a stale slice in this sauce.
Steam blackened veg: Move the blackened peppers to a bowl and cover to steam; this makes peeling the peppers a breeze.
Blend: Tear the bread into pieces, peel and tear the pepper into pieces, and blend everything — the bread, vegetables, and nuts — while streaming in olive oil until you have a thick sauce.
And go! Ready a piece of toast, crackers, or an empty spoon for enjoying the sauce still warm from the blender. This is the moment you’ll fall in love with romesco.
Romesco, Rouille, and Romanesco?
Romesco, the sauce, is not to be confused with romanesco the vegetable — a relative of broccoli that looks like a green-hued cauliflower. Romesco the sauce is often aligned with rouille — a French sauce relative to romesco. Rouille is most famously served with bouillabaisse (a vibrant seafood stew) and served with bread. Like romesco, roasted red peppers are a primary ingredient. Unlike romesco, rouille typically doesn’t include nuts as a thickener.

(Image credit: Joe Lingeman)
Shortcut Romesco
Let’s say you need to throw together a batch of romesco in a hurry — you don’t have time for broiling and steaming the peppers or even toasting the bread. Here are a few shortcuts you can take.

Use 1 cup of the blanched and toasted almonds and skip the hazelnuts all together. If you’re feeling extra fancy, use marcona almonds and skip the toasting too.
Toast 2 ounces or about 1/2 cup of panko breadcrumbs in a dry skillet for 3 to 5 minutes over medium high heat, and ditch the bread slice called for here.
Use jarred roasted red peppers. Drain them very well before blending.
Ultimately, remember that romesco is meant to make the most of leftovers and is adapted to whatever you have in the kitchen. You can skip the tomato (many romesco sauces do) and switch up the nuts. Keep the portion of olive oil, garlic, peppers, and paprika the same and you can’t lose.

How to Use Romesco Sauce
Romesco walks the line between dip, sauce, and condiment. You can serve it with bread or chips for dipping or spoon it over grilled fish, roasted meat, or charred vegetables as a sauce. Personally, I love it smeared on bread as a base for vegetable sandwiches or between a crunchy piece of toasted bread and creamy scrambled eggs.

You can also use romesco sauce where you might use pesto — folded into warm pasta or drizzled over bowls of rice and vegetables. Thinned with a little olive oil and red wine vinegar, it makes for a hearty dressing for simple salads.

Brush bread with oil and prepare vegetables. Brush both sides of the bread with 1 tablespoon of the olive oil. Place on one side of a baking sheet. Place the tomato and bell pepper halves skin side up on the other side of the baking sheet. Press down on the bell pepper with the heel of your hand to flatten it slightly.
Brush bread with oil and prepare vegetables. Brush both sides of the bread with 1 tablespoon of the olive oil. Place on one side of a baking sheet. Place the tomato and bell pepper halves skin side up on the other side of the baking sheet. Press down on the bell pepper with the heel of your hand to flatten it slightly.

Toast the bread and blacken the vegetables. Place the baking sheet under the broiler. Flip the bread once the first side is lightly toasted, after about 1 1/2 minutes. Once the second side is toasted, after another 30 seconds, remove the bread from the baking sheet. Continue to broil the tomato and bell pepper until their skins blacken, about 9 minutes more. Broilers vary, so keep an eye on how quickly the ingredients cook.
Steam vegetables and peel. Transfer the tomato and bell pepper to a bowl. Cover tightly with a pot lid, aluminum foil, or plastic wrap and set aside to steam until cool enough to handle, about 5 minutes. Peel and discard the skin from the tomatoes and bell peppers.
Steam vegetables and peel. Transfer the tomato and bell pepper to a bowl. Cover tightly with a pot lid, aluminum foil, or plastic wrap and set aside to steam until cool enough to handle, about 5 minutes. Peel and discard the skin from the tomatoes and bell peppers.
7. Torn bread, garlic, almonds, hazelnuts, salt, paprika & red pepper flake in food processor
8. Bread → red pepper flake ground to coarse meal
Blend the sauce. Tear the toasted bread into bite-sized pieces and place in the bowl of the food processor fitted with the blade attachment. Add the garlic, almonds, hazelnuts, salt, paprika, and red pepper flakes. Process until the nuts are ground into a coarse meal, about 45 seconds. Add the bell pepper, tomato, and vinegar and blend until smooth, about 30 seconds. With the motor running, drizzle in the remaining 6 tablespoons of olive oil and process until incorporated.

Instructions
Arrange oven racks and heat broiler. Position the top oven rack as close as possible to the broiling element in the oven. Heat broiler to high.
Brush bread with oil and prepare vegetables. Brush both sides of the bread with 1 tablespoon of the olive oil. Place on one side of a baking sheet. Place the tomato and bell pepper halves skin-side up on the other side of the baking sheet. Press down on the bell pepper with the heel of your hand to flatten it slightly.
Toast the bread and blacken the vegetables. Place the baking sheet under the broiler. Flip the bread once the first side is lightly toasted, after about 1 1/2 minutes. Once the second side is toasted, after another 30 seconds, remove the bread from the baking sheet. Continue to broil the tomato and bell pepper until their skins blacken, about 9 minutes more. Broilers vary, so keep an eye on how quickly the ingredients cook.
Steam vegetables and peel. Transfer the tomato and bell pepper to a bowl. Cover tightly with a pot lid, aluminum foil, or plastic wrap and set aside to steam until cool enough to handle, about 5 minutes. Peel and discard the skin from the tomatoes and bell peppers.
Blend the sauce. Tear the toasted bread into bite-sized pieces and place in the bowl of the food processor fitted with the blade attachment. Add the garlic, almonds, hazelnuts, salt, paprika, and red pepper flakes. Process until the nuts are ground into a coarse meal, about 45 seconds. Add the bell pepper, tomato, and vinegar and blend until smooth, about 30 seconds. With the motor running, drizzle in the remaining 6 tablespoons of olive oil and process until incorporated.
Recipe Notes
Storage: Refrigerate leftovers in an airtight container for up to 1 week, or freeze in ice cube trays for up to 3 months.
Hazelnut substitute: Use 1 cup of the blanched and toasted almonds and skip the hazelnuts all together. If you’re feeling extra fancy, use marcona almonds and skip the toasting too.
Bread substitute: Toast 2 ounces of about 1/2 cup of panko breadcrumbs in a dry skillet for 3 to 5 minutes over medium high heat, and ditch the bread slice called for here.